Pressure-sensitive transfer elements

ABSTRACT

Pressure-sensitive transfer elements for the pressure placement of automatically sensible images comprising a multiplicity of evenly visually spaced vertical columns of sensible composition capable of generating a multiplicity of voltage signals characteristic of each image being sensed, and the method of sensing such images.

United States Patent Newman Mar. 7, 1972 [54] PRESSURE-SENSITIVE TRANSFER [56] References Cited ELEMENTS UNITED STATES PATENTS [72] Newman 1,911,592 5/1933 Supligeau ..117/361 [73] Assignee: Columbia Ribbon and Carbon Manuiac- 3,099,571 7/1963 Maierson et al. ....1 17/36.l turing C0,, lnc., Glen Cove, NY. 3,138,515 6/1964 Dritz ....117/36.1 3,351,948 11/1967 Bonn ....l l7/36.1 [221 31 1969 3,404,021 10/1968 Newman et al. ..1l7/36.1 [2]] Appl. No.: 873,391

Primary Examiner--Murray Katz Related US. Application Data Attorney-Johnson and Kline [63] Continuation-impart of Ser. No. 639,374, .May 18,

1967, abandoned. [57] ABSTRACT Pressure-sensitive transfer elements for the pressure place- [52] US. Cl. ..1l7/36.1, 1 17/ 155 UA, l 17/ 157 ment of automatically sensible images comprising a multiplici- [51] Int. Cl ..B4lm 5/10 ty of evenly visually spaced vertical columns of sensible com- [5 8] Field of Search ..1 17/36.1 position capable of generating a multiplicity of voltage signals characteristic of each image being sensed, and the method of sensing such images.

2 Claims, 4 Drawing Figures PRESSURE-SENSITIVE TRANSFER ELEMENTS This application is a continuation-in-part of parent application Ser. No. 639,374, filed May 18, 1967, now abandoned.

In the field of automatic sensing, including magnetic and optical sensing, characters are formed of solid magnetically sensible or optically sensible deposits in the form of visually recognizable images conforming in size and shape to set standards such as the E-l 3B font type specified by the American Banking Association for magnetic characters. States in simplified terms, the automatic sensing systems rely on the difference in physical structure between the characters being sensed to trigger different voltage signals, each series of signals per character being characteristic of that particular character.

According to the known sensing systems, each character is separated electronically into seven vertical strips so that each strip is sensed and the signal recorded and stored until the total character is sensed and the readings combined to recognize the given character. The main difficulty with such systems is to produce sensible images, particularly magnetic images, using pressure-sensitive transfer means carrying a layer of transfer composition which is tough and smudge resistant and yet capable of sharp uniform transfer to the record sheet under the effects of imaging pressure.

In an effort to meet these requirements, most transfer compositions are formulated from resinous or cellulosic film-forming binder materials. These materials are tough and smudge resistant but this leads to the disadvantage that they sometimes transfer incompletely to the record sheet to produce characters having voids, or transfer in excess so as to produce characters which have filled-in areas or trailing edges attached. These defects may result in an inaccurate reading of the character or a rejection thereof by the sensing device.

The present invention is concerned with novel pressure-sensitive transfer elements for the placement of automatically sensible characters which are smudge resistant, sharp, clear and substantially defect free and which are capable of more accurate sensing than solid characters in either the conventional sensing processes or in the novel sensing process made possible by the present invention.

According to the present invention, I have discovered that it is possible to provided pressure-transferable sensible compositions which are capable of producing sensible characters which are of uniform appearance, are smudge resistant and can be sensed more reliably and accurately than prior known compositions. The pressure-transferable compositions of the present invention provide characters which comprise a series of equally and narrowly visually spaced fine columns of automatically sensible composition, and this result is obtained by printing or otherwise providing the transferable composition on the transfer sheet foundation as a series of equally and narrowly spaced fine continuous columns of imaging material which is based upon a synthetic thermoplastic resinous binder material so as to be hard, smudge resistant and resistant to spreading under the effects of imaging pressure, whereby such columns of imaging material locally transfer as such to a copy sheet under the effects of imaging pressure to produce images which consist of visually-spaced columns of automaticallysensible imaging composition.

The figures of the drawing illustrate the various embodiments of the present invention.

FIG. 1 is a plan view of a pressure-sensitive transfer sheet according to one embodiment of the present invention.

FIG. 2 is a top view ofa credit card useful according to this invention.

FIG. 3 is a view of the credit card of FIG. 2 along the line 22.

FIG. 4 is a top view of a record card imaged with the transfer sheet of FIG. 1.

The essence of the present invention is the twofold discovery that (a) characters of greater uniformity can be reliably produced in the form of discontinuous characters consisting ofa series of equally and narrowly spaced fine columns, and (b) characters of this type are capable of more accurate sensing because of their greater uniformity and because they are constituted of a series of fine columns, each of which is a sensible front which the automatic sensing means can detect. Both of these considerations are critical to the present invention. If the present compositions are applied as a continuous layer to a transfer sheet, they cannot be reliably transferred as uniform, sharp images because their hardness results in the formation of filled-in characters and characters with trailing edges or hangers attached. The addition of large amounts of waxes will overcome this transfer problem but will result in a spreadable composition which, if applied to the transfer sheet in the form of visually spaced columns, will spread and merge during pressure transfer to form continuous images which do not consist of visually spaced columns and which are not capable of being sensed with the degree of accuracy afforded by the present columnar images.

According to one embodiment of this invention, pressuresensitive transfer sheets are provided which carry pressuretransferable automatically sensible composition in the form of uniformly narrowly spaced fine vertical continuous lines as illustrated by FIG. 1 of the drawing. The transfer sheet 10 comprises a flexible foundation sheet 11 such as paper or plastic film carrying pressure-transferable composition containing magnetically sensible pigment such as iron oxide or optically sensible pigment such as carbon black in the form of parallel uniformly spaced fine narrow lines 12 as illustrated by the magnified section of FIG. 1. The dimensions and spacing of the lines 12 are critical to the present invention in that a character to be sensed must consist of at least four such lines. For magnetic sensing, using the El3B font characters, each character should contain seven lines. Therefore the lines must be present on the transfer sheet at the rate of from about 40 per inch up to about I60 per inch depending upon the size and type ofcharacters being produced.

Transfer sheets of this type preferably are prepared by means of known printing techniques such as with intaglio or relief printing rollers of the required dimensions, using solvent-applied inks based upon film-forming binder material and sensible pigment. The printing ink is applied to either the peaks or the hollows of the printing cylinder, depending on which process is used, and is then printed onto the transfer sheet foundation as uniformly spaced parallel fine continuous lines of the desired dimensions. Thereafter the solvent is evaporated.

It should be understood that the transferable composition of FIG. 1 may be in the form of a uniform screen of horizontal and vertical continuous columns spaced as indicated.

The present method also contemplates the use of conventional transfer elements based upon film-forming binder materials which normally transfer sensible composition as a mass in areas impressed by imaging pressure. According to the present invention, this effect is overcome by the use ofimpression means in the form of characters which are etched or otherwise formed so as to have an impression surface consisting ofequally and narrowly spaced fine raised columns oflines of the required dimensions. Such impression means cause the layer of sensible transfer composition to transfer sharply and without spreading under the effect of imaging pressure in the form of narrowly spaced fine lines to form sensible characters of the desired type.

FIGS. 2 and 3 of the drawing illustrate a credit card having raised characters of the type contemplated supra. The card 30, such as plastic or metal, contains embossed correct reading surface characters 31 and reverse-reading raised characters 32 which are vertically interrupted so as to consist of a series of equally and narrowly spaced fine raised columns, more clearly illustrated by FIG. 3. When the credit card is superposed with a transfer sheet having a layer of pressure-transferable automatically sensible composition and a record sheet and subjected to roller pressure in a pressure device, the images formed on the record card are correct reading and correspond to the raised images on the credit card.

lOl026 mm EXAMPLE A pressure-sensitive magnetic transfer element according to FIG, 1 is prepared as follows: The magnetic ink is formulated by mixing the following ingredients to a uniform printable consistency:

Ingredients Parts by Weight Ethyl hydroxyethyl cellulose 5 Refined rapeseed oil 12 Castor oil 4 Magnetic iron oxide 24 Toluol 55 Total: 100

The ink composition is printed onto a 0.5 mil Mylar film foundation by means of a printing cylinder having thin narrowly spaced circumferential grooves and 100 raised areas or circumferential peaks per inch. The ink is applied as a thin layer of 0.6 mil thickness to an offset application roller and transferred to only the peak areas of the printing roller. The printing roller is then contacted with the Mylar film to transfer the magnetic ink thereto in the form of thin narrowly spaced parallel lines. Heat is applied to evaporate the toluol and solidify the ink as pressure-transferable continuous lines having a thickness of about 0.3 mil and numbering 100 per inch.

Record sheets pressure imaged by means of the transfer elements, such as sheets or ribbons, of the example are magnetically 0r optically sensed in conventional manner with more accurate results than heretofore possible because of their uniform density and sharpness and their lack of voids or other defects.

Similarly they are adapted to being sensed by a novel process in which the sensing head is in continuous electrical contact, rather than operating in pulses controlled by a timer, and senses each of the vertical columns constituting each character and transmits a signal for each such column which is stored until the total character is sensed and identified. In order to be sensible according to this process, it has been found that the images must be sufficiently discontinuous that the spacing of the columns of sensible composition is perceptible to the unaided eye, i.e., the columns are visually spaced. Otherwise the images are so continuous that the automatic sensing device cannot detect a series of fronts. I

The screen-type characters produced according to one embodiment of this invention have horizontal columns of lines as well as vertical columns and thus are capable of being sensed in both directions for purposes of double verification of the identity of each character. This may be cumbersome for some operations but is practical for other operations where the necessity of avoiding error outweighs the extra steps involved.

The imaging compositions suitable for use according to the present invention are those based upon a film-forming binder material and a sensible pigment. Preferred binders are the cellulosic film formers such as ethyl cellulose and hydroxyethyl cellulose. Vinyl resins are also suitable, such as polyvinyl acetate and polyvinyl butyrate. Such compositions preferably are free of wax but may contain minor amounts of wax and/ or amounts of oil to improve their frangibility without rendering them so soft that they spread during transfer.

I claim:

1. A pressure-sensitive transfer element for the production of automatically sensible images which comprises a flexible foundation having thereon from about 40 to about thin,

visually s aced parallel vertical continuous columns per linear ll'lCll wrdt of such foundation of a solvent-applied composition comprising a film-forming binder material from the group consisting of cellulose plastics and vinyl resins and automatically sensible imaging material, said compositions being transferable from said foundation without spreading in the form of said thin, visually spaced parallel vertical columns under the effects of normal imaging pressure to form automatically sensible discontinuous images consisting of said thin, visually spaced vertical columns.

2. A transfer element according to claim 1 in which said transfer sheet has thereon a screen comprising said thin visually spaced parallel vertical columns and from about 40 to about 160 thin, visually spaced parallel horizontal continuous columns per linear inch height of said foundation comprising said solvent-applied composition. 

2. A transfer element according to claim 1 in which said transfer sheet has thereon a screen comprising said thin visually spaced parallel vertical columns and from about 40 to about 160 thin, visually spaced parallel horizontal continuous columns per linear inch height of said foundation comprising said solvent-applied composition. 